Thorax 1 Flashcards
How many pair of ribs is. the bony thorax made up of?
12 ribs
How many sections is the bony thorax divided into?
Divided into 5 sections
What type of system is the bony thorax and what does it aid?
Protective system as well as aiding in expansion
What may some patients complain of in upper epigastric region where the xiphoid process is?
Some patients complain of lump in upper epigastric region, due to calcification of xiphoid process
What are true ribs and what ribs are they?
True ribs attach directly to the sternum
Ribs 1-7
What are false ribs and what ribs are they?
These are ribs that fuse together to come together and join to the sternum
Ribs 8-10
What are floating ribs and what ribs are they?
These are the lowermost ribs that are attached only to vertebrae, and not to sternum
Ribs 11-12
What is the superior thoracic aperture also known as and what does it emphasise the importance of?
Superior thoracic aperture known anatomically as the “thoracic inlet,” but clinically as the “thoracic outlet” emphasizing the important nerves and arteries that pass from the thorax to the neck and upper limb.
What does the superior thoracic aperture allow the passage of?
It allows for the passage of nerves, vessels, and viscera from the neck into the thoracic cavity.
Why are the anatomical positions important in the superior thoracic aperture?
Anatomical positions important when planning surgeries or procedures
What does the spinous process angle in thoracic vertebrae allow?
Spinous process angle allows forward flexion and movement of thoracic rib cage
What does the vertebral notch in thoracic vertebrae allow?
Vertebral notch allows nerve to come out in between to connect to spinal cord
What do pedicle in thoracic vertebrae hold the body to?
-Pedicles hold the body to the rest of the process
Why are thoracic vertebrae porous?
Vertebrates are porous to allow blood vessels to vasculate
Where are fracture most likely to occur on a rib?
Fractures more likely to occur at angled section
Where do costal groove lie and what do they contain?
Costal groove lie underneath each rib and contain our vessels
Order of vessels in costal groove from superior to inferior
From Superior to inferior(Vein, Artery, Nerve)
VAN
What is a cervical rib and due to what?
Cervical rib is an extra rib due to an elongation of transverse process of cervical vertebrae
What symptoms can cervical ribs cause?
Can cause tingling in the fingertips
What can cervical ribs impinge?
Impinge nerve routes
Where do scalene muscles at the first rib come from?
Scalene muscles come from transverse processes from C spine.
How many scalene muscles are there and what are they labelled as?
3 of them. Anterior, middle, posterior
What do scalene muscles help with the division of?
Help with the division of arterial and venous system
Why is the first rib rarely fractured?
This rib is rarely fractured because of its protected position posteroinferior to the clavicle
Does the first rib have a costal groove?
No
What does the 11th and 12th rib not have that other ribs may do? What does the 12th rib not have that the 11th rib does?
- No neck
- No tubercle
- 12th rib has no costal groove whereas 11th does
What is the origin of the clavicular part of the pectoralis major muscle?
Anterior surface of medial half of clavicle
What is the origin of the sternocostal part of the pectoralis major muscle?
Anterior surface of sternum, costal cartilages of ribs 1-6
What is the origin of the abdominal part of the pectoralis major muscle?
Anterior layer of rectus sheath
Where is the insertion of the pectoralis major muscle?
Crest of greater tubercle of humerus
What are the actions allowed by the pectoralis major muscle?
Shoulder joint: Arm adduction, arm internal rotation, arm flexion
What is the innervation by the pectoralis major muscle and at what vertebral level;?
Lateral and medial pectoral nerve(C5-T1)
What is the bloody supply of the pectoralis major muscle?
Pectoral branches of thoracoacromial artery, perforating branches of internal thoracic artery
What is the origin of pectoralis minor muscle?
Anterior surface, costal cartilage of ribs 3-5
Where is the insertion of the pectoralis minor muscle?
Medial border and coracoid process of scapula
What is the innervation by in pectoralis minor muscle and at what vertebrae level?
Medial and lateral pectoral nerves(C5-T1)
What is the blood supply by in pectoralis minor muscle ?
- Thoracoacromial artery(Pectoral and deltoid branches)
- Superior thoracic artery
- Lateral thoracic artery
What is the function of pectoralis minor muscle?
Scapulothoracic joint:
- Draws scapula anteroinferiorly
- Stabilises scapula on thoracic wall
What is the origin of the external intercostal muscle?
Inferior border of ribs
Where is the insertion of the external intercostal muscles?
Superior border of immediate rib below
What is the action of the external intercostal muscle?
- Elevate ribs during forced inspiration
- Supports intercostal spaces and thoracic cage
What are external intercostal muscles innervated by?
Intercostal nerves
What is the blood supply of external intercostal muscles?
Anterior and posterior intercostal arteries
What is the origin of the internal intercostal muscle?
Costal groove of ribs
Where is the insertion of the internal intercostal muscle?
Superior border of immediate rib below
What are the actions of internal intercostal muscles?
- Depress ribs during forced expiration
- Support intercostal spaces and thoracic cage
What innervates the internal intercostal muscles?
Intercostal nerves
What is the blood supply for internal intercostal muscles?
- Anterior intercostal artery
- Posterior intercostal artery
- Internal thoracic artery
- Musculophrenic artery
- Costocervical trunk
What is the origin of the innermost intercostal muscle?
Costal groove of ribs
Where is the insertion of innermost intercostal muscle?
Superior border of immediate rib below
What is the action of innermost intercostal muscle?
- Depress ribs during forced expiration
- Support intercostal spaces and thoracic cage
What innervates the innermost intercostal muscle?
Intercostal nerves
What is the blood supply for innermost intercostal muscle?
- Anterior intercostal artery
- Posterior intercostal artery
- Internal thoracic artery
- Musculophrenic artery
- Costocervical trunk
What is the origin of the transversus thoracis muscle?
Inferoposterior surface of body of sternum and xiphoid process; sternal ends of costal cartilages of ribs 4-7
Where is the insertion of the transversus thoracis muscle?
Internal surface of costal cartilages of ribs 2-6
What is the action of transversus thoracis muscle?
- Depresses ribs during forced expiration
- Supports intercostal spaces and thoracic cage
What innervates transversus thoracis muscle?
Intercostal nerves
What is the blood supply of the transversus thoracis muscle?
Sternal branches of internal thoracic artery
What is the origin of the superior part of the serratus anterior muscle?
-Ribs 1-2, Intercostal fascia
What is the origin of the middle part of the serratus anterior muscle?
Ribs 3-6
What is the origin of the inferior part of the serratus anterior muscle?
Ribs 7-8/9/19(+external oblique muscle)
Where is the insertion of the superior part of the serratus anterior muscle?
Anterior and posterior surface of superior angle of scapula
What is the insertion of the middle part of the serratus anterior muscle?
Anterior surface of entire medial border of scapula
What is the insertion of the inferior part of the serratus anterior muscle?
Anterior and posterior surfaces of inferior angle of scapula
What innervates the serratus anterior muscle and at what vertebrate level?
Long thoracic nerve(C5-C7)
What is the blood supply for the serratus anterior muscle?
- Superior and lateral thoracic arteries
- Thoracodorsal artery branches
What is the function of serratus anterior muscles?
Scapulothoracic joint:
- Draws scapula anterolaterally
- Suspends scapula on thoracic wall
- Rotates scapula
Where do intercostal nerves run within?
These run within the costal grooves along the lower edge of the ribs
What happens to the intercostal nerve in the 8th intercostal space?
In the 8th intercostal space, the nerve crosses deep to the costal margin and enters the anterior abdominal wall
What is the dermatome?
Dermatome is an area of skin that is supplied by a single spinal root
What dermatome is the nipple area?
Nipple area is dermatome T4
What dermatome is the umbilical area?
Umbilical area is dermatome T10
What can affect dermatomes?
Can be affected by herpes virus
What are the origins of the vessels vasculating the thorax?
Origins are:
- Subclavian artery
- Thoracic aorta
- Axillary artery
What are intercostal spaces supplied by?
Intercostal spaces are supplied by intercostal arteries
How many posterior intercostal arteries are there?
There are 11 posterior intercostal arteries
Where do the upper 2 posterior intercostal arteries arise from and what particular trunk?
Costocervical trunk of subclavian artery
Where do the lower 2 posterior intercostal arteries arise from?
Lower 9 arise from descending thoracic aorta
How many anterior intercostal arteries are there?
There are 9 anterior intercostal arteries
Where do the upper 6 anterior intercostal arteries arise from?
Upper 6 arise from internal thoracic artery
Where do the lower 3 anterior intercostal arteries arise from?
Lower 3 arise from Musculo-phrenic artery
Where does the internal thoracic artery arise from?
Arises from the 1st part of the subclavian artery
How does the internal thoracic artery terminate and by dividing into what?
It terminates by dividing into the musculophrenic and superior epigastric arteries
What vasculates the diaphgram?
Internal mammary artery vasculates diaphragm
What level of the ribs does the breast overlie?
Overlies the 2nd-6th rib
What muscle does 2/3 of the breast rest on?
2/3s of it rests on pectoralis major
What muscle does 1/3 of the breast rest on?
1/3s on serratus anterior
What is the structure of the breast?
- Modified sweet gland
- Conical in shape
- Lies in superficial fascia of the front of the chest
- Has a base, apex and tail
- Extends from the lateral margin of the sternum to mid-axillary line
- Has no capsule
What are lobules of the breast drained by?
Lobules of the breast are drained by a lactiferous duct that usually opens independently on the nipple
What do lactiferous ducts give rise to and what does it constitute?
Lactiferous ducts give rise to buds that form 15-20 lobules of glandular tissue, which constitute the gland.
What glands does areola contain and when do they enlarge, secreting what?
Areola contains numerous sebaceous gland and enlarge during pregnancy and secrete oily substance that provides a protective lubricant for the areola and nipple
What is the physical appearance of the areola?
Is the dark pink brownish circular area of skin that surrounds the nipple
What are nipples and what do they not have?
Nipple ae conical prominences in the centres of the areolae. They have no fat, hair or sweat glands
Where does the nipple lie in terms of the intercostal spaces?
The nipple lies opposite 4th intercostal space
What muscle fibres does the nipple contain?
It contains smooth muscle fibres
What do fibrous septae(Suspensory ligaments) allow the mammary glands to attach to?
Fibrous septae(Suspensory ligaments) allow mammary glands to firmly attach to the dermis of the overlying skin.
What are copper ligaments?
Cooper’s ligaments are connective tissue in the breast that help maintain structural integrity
What is the blood supply for the breast and principally via what branches?
Is from the axillary artery, principally via its lateral thoracic and acromiothoracic branches
1. Perforating branches of internal thoracic artery 2. Mammary branches of lateral thoracic artery 3. Mammary branches of intercostal arteries
What plexus is found at the base of the nipple?
Circular venous plexus are found at the base of the nipple
Where do the veins of the circular venous plexus drain into?
Veins of this plexus drain into axillary and internal thoracic veins
How many groups is lymphatic drainage arranged into and where do they lie?
Arranged into 5 groups which lie in the axillary fat
What are the 5 groups of the lymphatic drainage and where do each of them lie?
- Pectoral(anterior) group:
- Which lies in pectoralis major along lateral thoracic vessels
- Subscapular(posterior) group:
- Which lies on posterior wall of axilla on lower border of subscapularis along subscapular vessels
- Brachial(lateral) group:
- Which lies on lateral wall of axilla along the axillary vessels
- Central group:
- Lies in at the center
- Apical group
- Lies at apex of axilla
What is the subclavian lymph trunk forbed by and where does it open?
Subclavian lymph trunk is formed by the union of efferent lymph vessels of apical group. It usually opens in the subclavian vein. On the left side it usually opens into the thoracic duct.
